Since this thread started I noticed several other companies advertising the same set up. Why is everyone saying they are all junk again? Same comments I heard when the Civilian M4's started popping up after Colt.
My first M4's were BM and Armalite. I was told I was ripped off, It would break apart, Make a good wall hanging. Colt is the only real M4. Years later, shot weekly about the average for use. Armalite is still running with it's original upper and lower, used in two SFAUC courses, don't ask

The BM lower is still being used. Never had problems. I know Colt is a better quality Weapon, no doubt. But is your M4 going to be bouncing around a Hummer, Jumped from Planes, exposed to over pressure rutinely....etc
Take the same approach as you would with a new PC Operating system (Vista)Wait.
If the situation permits you. You might have some nice HK's in your Arms room. While the department up the street is attending Front Sites two week Combat Carbine Course. With the money they saved buying elsewhere. There is a lot of baggage to think about in choosing a new weapon for a unit or individual. Training being first on the list.